Summary:
This is one of only two aromatic-ring-cleavage pathways found in Escherichia coli (for the second one, see phenylacetate degradation I (aerobic)). That Escherichia coli can degrade aromatic acids suggests a wider natural distribution for Escherichia coli than the anaerobic environment of the animal gut. [Burlingame83] In the utilization of aromatic acids as a carbon and energy source, Escherichia coli employs a branched meta-cleavage pathway for the degradation of 3-phenylpropionate and 3-(3-hydroxyphenyl)propionate. Degradation of these two compounds ultimately yields succinate, acetaldehyde and pyruvate. Acetaldehyde is further metabolized to yield acetyl-CoA. The pathway has eight known steps, which makes it among the longest catabolic sequences in Escherichia coli. [Burlingame86, Bugg93, Ferrandez97]